CN101714359B - Head suspension and method of manufacturing head suspension - Google Patents

Abstract

The head suspension 31 has a piezoelectric element 13 that deforms in response to a voltage applied thereto, a base 33 that has an attachment member for attaching the piezoelectric element 13 , and a load beam 35 , and The load beam 35 has a flexure 39 . The front end of the load beam 35 moves in the swing direction according to the deformation of the piezoelectric element 13 . The head suspension 31 includes an adhesive that attaches the piezoelectric element 13 to an attachment member. Apply and harden the adhesive on the attached parts one by one. At least one adhesive that is first applied and cured at the attachment part is electrically insulating. The head suspension 31 properly maintains electrical insulation between the piezoelectric element 13 and the attached member, fully exhibits the original function, and obtains rigidity balance and proper vibration characteristics.

Description

Head suspension and method of manufacturing head suspension

technical field

The present invention relates to a head suspension having a piezoelectric element that is attached to the head suspension by an electrically insulating adhesive and deforms in response to a voltage applied thereto. The invention also relates to a method of manufacturing such a head suspension.

Background technique

Small precision information devices are rapidly developing, and for such devices, the demand for microactuators capable of positional control over very small distances is increasing. Devices that particularly require such microactuators include optical systems for correcting focus and tilt, inkjet printers for controlling ink heads, and disk drives for controlling magnetic heads.

Disk drives had a pressing problem to solve, namely increasing storage capacity. If the storage capacity of each disk in the disk drive increases, the storage capacity of the disk drive increases. If the number of tracks per inch (TPI, tracks per inch) on the magnetic disk increases, the storage capacity or recording density of the magnetic disk increases without changing the diameter of the magnetic disk. For this, the width of each track on the disk must be narrow. To handle such narrow tracks on a magnetic disk, the heads of the head suspension in the disk drive must be precisely positioned in the direction across the tracks. In order to achieve precise positioning, an actuator that can accurately move and position the magnetic head of the head suspension in a very small area is required.

In order to meet this need, the applicant of the present invention has proposed a head suspension for a magnetic disk drive in Japanese Unexamined Patent Application Publication No. 2002-50140. The head suspension includes a base, a connecting plate having a hinge thinner than the base, a load beam provided with a flexure and a magnetic head, and a pair of piezoelectric elements.

This related art employs a dual actuator system for positioning a magnetic head including a voice coil motor and a pair of piezoelectric elements each made of PZT (lead zirconate titanate).

The piezoelectric element drives the front end of the load beam precisely in the lateral direction (swing direction) of the head suspension. The dual-actuator system using the voice coil motor and the piezoelectric element more precisely positions the magnetic head attached to the front end of the head suspension, compared to the single-actuator system using only the voice coil motor.

An important issue for a head suspension employing a dual-actuator system is how to mount the piezoelectric element to the head suspension.

As a solution to this problem, the applicant of the present invention proposed a head suspension for a magnetic disk drive in Japanese Unexamined Patent Application Publication No. 2002-184140 (particularly, paragraphs 0024 to 0026 and the adhesive layer). The head suspension includes a load beam, a flexure attached to the load beam, an actuator base including a mount, and a pair of piezoelectric elements. The actuator base has an attachment part to which a pair of piezoelectric elements is attached through an electrically insulating adhesive layer.

According to this related art, a piezoelectric element is provided at a predetermined position on an actuator substrate with a gap between the piezoelectric element and the actuator substrate and an adhesive is applied to the gap.

If the amount of adhesive applied to the gap is too small, the electrical insulation between the piezoelectric element and the actuator substrate will be insufficient. If the amount of adhesive is too large, the applied adhesive will ooze and spread.

That is, if too little adhesive is applied, insulation failure will occur between the piezoelectric element and the actuator substrate, thereby deteriorating the function of the head suspension. If too much adhesive is applied, the adhesive will seep and spread to reach the flexure of the load beam, deteriorating the rigidity balance and vibration characteristics of the head suspension.

Contents of the invention

An object of the present invention is to provide a head suspension capable of properly maintaining electrical insulation between a piezoelectric element and an attachment part of the head suspension to which the piezoelectric element is attached and sufficiently perform the original function of the head suspension. Another object of the present invention is to provide a method of manufacturing such a head suspension.

To achieve this object, an aspect of the present invention provides a head suspension having a piezoelectric element that deforms in response to a voltage applied thereto, a base that serves as a At the opening of the attachment part to which the piezoelectric element is attached, the load beam is fixed to the base so that the front end of the load beam moves in a swing direction according to deformation of the piezoelectric element. The head suspension includes: a support formed in the opening configured to support an electrode surface of the piezoelectric element; and a plurality of adhesive layers formed on the support for attaching the piezoelectric element Affixed to said support, a layer of adhesive in contact with said support is electrically insulating.

This aspect of the invention employs multiple adhesive layers to secure the piezoelectric element to a support that supports the electrode surface of the piezoelectric element. An adhesive layer in contact with the support is electrically insulating. This aspect achieves electrical isolation between the piezoelectric element and the attachment part and allows the head suspension to work completely.

Description of drawings

FIG. 1 is a perspective view showing a head suspension according to an embodiment of the present invention;

FIG. 2 is a perspective view showing a piezoelectric actuator disposed in the head suspension of FIG. 1;

Fig. 3 is a sectional view taken along line A-A of Fig. 2;

Fig. 4 is a bottom view showing the head suspension of Fig. 1;

5A is a cross-sectional view partially showing a layered adhesive at an opening (attachment member) of the head suspension of FIG. 1;

Figure 5B is a cross-sectional view partially showing a layered adhesive according to a variation of the embodiment shown in Figure 5A;

6 is a schematic diagram showing an adhesive applying system for applying adhesive to a piezoelectric element attachment part of a head suspension;

7 is a view illustrating a method of manufacturing a head suspension according to an embodiment of the present invention;

8 is a view illustrating a method of manufacturing a head suspension according to another embodiment of the present invention; and

Fig. 9 is a plan view showing a head suspension according to a modification of the present invention.

Detailed ways

A head suspension and a method of manufacturing the head suspension according to embodiments and modifications of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a head suspension 31 according to an embodiment of the present invention.

The head suspension 31 includes a piezoelectric actuator 11, a base 33 (corresponding to "substrate" specified in the claims), a load beam 35, a connecting plate 37 working as a hinge, etc., wherein the piezoelectric actuator 11 is formed in response to The piezoelectric element 13 is composed of a piezoelectric element 13 deformed by applying a voltage thereto.

The base 33 has an opening 43 (corresponding to an “attachment member” specified in the claims) in which the piezoelectric element 13 is embedded. The piezoelectric element 13 is deformed in response to the applied voltage to move the front end of the load beam 35 in the swing direction (ie, the lateral direction of the head suspension 31 ).

The base 33 is made of, for example, a stainless steel thin plate having a thickness of about 150 to 200 μm. The base 33 includes a pair of flexible members 41 a and 41 b each having a U-shape, an opening 43 for accommodating the piezoelectric element 13 , and a circular lug 45 . Each of the flexible members 41 a and 41 b is bent outward at a position corresponding to the side of the piezoelectric element 13 . The base 33 is fixed to the front end of an actuator arm (not shown), which is rotated by a voice coil motor (not shown).

The base 33 can be made of light metal such as aluminum alloy and cladding material consisting of light metal and stainless steel. Light metal can reduce the inertia of the base 33 , increase the resonance frequency of the head suspension 31 in the swing direction, and improve the tracking performance of the head suspension 31 .

Instead of providing the base 33 with the flexible parts 41a and 41b and the opening 43, an actuator plate 34 with the flexible parts 41a and 41b and the opening 43 may be used. In this case, the rear end of the actuator plate 34 is placed on the base 33 and fixed to the base 33 by eg laser welding.

The head suspension 31 may employ both the base 33 and the actuator plate 34 , or only the base 33 . In the following description, it is assumed that the actuator plate 34 and the base 33 are integrally formed for simplicity of description.

The load beam 35 has a flexure 39 . The flexure 39 is made of a sheet metal spring which is thinner and more precise than the load beam 35 . The front end of the flexure 39 is provided with a slider (not shown) having a magnetic head. The load beam 35 is made of a stainless steel plate having a thickness of approximately 30 to 150 μm, and is designed to apply a load to the slider. The load beam 35 has curved edges 36 a and 36 b to improve the rigidity of the load beam 35 . The rear end of the load beam 35 and the connecting plate 37 are integrally formed.

The load beam 35 can be made of light metal such as aluminum alloy or a cladding material consisting of light metal and stainless steel. Light metal can reduce the inertia of the load beam 35 , increase the resonance frequency of the head suspension 31 in the swing direction, and improve the tracking performance of the head suspension 31 .

The connecting plate 37 is made of an elastic metal plate having a thickness of about 30 μm. A part of the connection plate 37 has a hole 47 to reduce the rigidity of the connection plate in the thickness direction. On each side of the hole 47, there are hinges 49a and 49b bent in the thickness direction. The rear end of the connection plate 37 is placed on the front end of the bottom surface of the base 33 and fixed to the front end of the bottom surface of the base 33 by, for example, laser welding.

The piezoelectric actuator 11 attached to the head suspension 31 will be explained.

FIG. 2 is a perspective view showing the piezoelectric actuator 11 mounted to the head suspension 31 , and FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2 .

The piezoelectric actuator 11 is composed of a piezoelectric element 13 having a substantially rectangular shape. The piezoelectric element 13 is deformed in response to an applied voltage to drive a target part (load beam 35). More precisely, the piezoelectric element 13 deforms when a voltage is applied, or when the voltage applied thereto is stopped, or according to the level of the voltage applied thereto.

The piezoelectric element 13 includes first and second electrodes 15 and 17 , a common electrode 19 opposed to the first and second electrodes 15 and 17 , and an electrode disposed between the first and second electrodes 15 and 17 and the common electrode 19 . The piezoelectric material 21, the first and second electrodes 15 and 17 are arranged in a common plane and separated from each other by a predetermined distance.

The first and second electrodes 15 and 17 and the common electrode 19 may be made of a metal having low contact resistance, such as gold (Au). The first and second electrodes 15 and 17 have substantially the same shape and size. The common electrode 19 has substantially the same size and shape as the combination of the first and second electrodes 15 and 17 .

The piezoelectric material 21 is composed of a first piezoelectric material 21a and a second piezoelectric material 21b, wherein the first piezoelectric material 21a deforms according to the voltage applied to the first electrode 15, and the second piezoelectric material 21b deforms according to the voltage applied to the second piezoelectric material 21b. The voltage of the electrode 17 is deformed. The first and second piezoelectric materials 21a and 21b are arranged such that they are oppositely polarized. The first and second piezoelectric materials 21a and 21b are made of, for example, piezoelectric ceramics that are polarized to have a difference in polarization direction of 180 degrees from each other.

The operation of the piezoelectric actuator 11 will be explained. In FIG. 2, the side of the piezoelectric element 13 marked with "X" is the stationary side, the side marked with "Y" is the driving side, the first and second electrodes 15 and 17 are grounded, and the common electrode 19 receives Voltage.

When a voltage is received, the piezoelectric element 13 deforms into a trapezoid in which the end face 23 of the first electrode 15 contracts and the end face 25 of the second electrode 17 extends. As a result, the piezo element 13 moves a very small distance in the direction Z ( FIG. 2 ) to move the part attached to the drive side Y of the piezo element 13 (the load beam 35 ).

When the common electrode 19 is grounded and the first and second electrodes 15 and 17 receive a voltage, the piezoelectric element 13 moves a small distance in the direction -Z (opposite to the direction Z) to move the driving side attached to the piezoelectric element 13 Part of Y (load beam 35).

The piezoelectric actuator 11 requires three electrical systems for the first and second electrodes 15 and 17 and the common electrode 19 . This configuration simplifies the wiring to the piezoelectric element 13 and achieves reliability of the wiring.

The piezoelectric actuator 11 has a single piezoelectric element 13 to reduce the number of parts, minimize parts management, and reduce the cost of the head suspension 31 .

The head suspension 31 will be further explained.

4 is a bottom view showing the head suspension 31 of FIG. 1, FIG. A cross-sectional view showing a layered adhesive according to a modification of the present embodiment shown in FIG. 5A, and FIG. 7 is a view showing the process of attaching the piezoelectric element 13 to the attachment part of the head suspension 31, and FIG. 8 is a view showing the process of attaching the piezoelectric element 13 to the head suspension 31 view of another process of attaching parts.

The piezoelectric element 13 is embedded in an opening 43 formed in the base 33 of the head suspension 31 such that the first and second electrodes 15 and 17 are on top and the common electrode is on the bottom. The top surface of the base 33 is at the same height as the top electrode surface of the piezoelectric element 13 .

Front and rear ends of the peripheral edge of the opening 43 are partially etched to improve the adhesion of the non-conductive adhesive 51 . Partial etching forms supports 33a1 and 33a2. Each of the supports 33 a 1 and 33 a 2 has a surface to support the surface of the common electrode 19 of the piezoelectric element 13 .

There are a plurality of adhesive layers between the common electrode 19 of the piezoelectric element 13 and the supports 33a1 and 33a2, including a first non-conductive adhesive layer 51a1 and a second non-conductive adhesive layer 51b1 as shown in FIG. 5A.

The first non-conductive adhesive layer 51a1 preferably has a thickness of 10 μm or more in order to obtain electrical insulation between the common electrode 19 and the supports 33a1 and 33a2.

Between the piezoelectric element 13 and each of the front and rear vertical walls 43a of the opening 43, there is a gap 50 in which a third non-conductive adhesive layer 51c1 having an appropriate thickness is arranged.

The head suspension 31 according to the present embodiment may employ the conductive adhesive layer 51bb1 (FIG. 5B) instead of the second non-conductive adhesive layer 51b1. In this case, a device capable of ensuring electrical insulation between the common electrode 19 of the piezoelectric element 13 and the base 33 is required. For this reason, it is necessary to form the first non-conductive adhesive layer 51a2 for covering the vertical wall 43a when the first non-conductive adhesive layer 51a1 is formed. The first non-conductive adhesive layers 51a1 and 51a2 form an L-shaped continuous insulating layer to ensure electrical insulation.

The above-mentioned adhesive layer will be described in detail. The first non-conductive adhesive layers 51a1 and 51a2 are formed by applying and hardening the first non-conductive adhesive 51a. The second non-conductive adhesive layer 51b1 is formed by applying and hardening the second non-conductive adhesive 51b. The conductive adhesive layer 51bb1 is formed by applying and hardening the conductive adhesive 51bb. The third non-conductive adhesive layer 51c1 is formed by applying and hardening the third non-conductive adhesive 51c.

The first to third non-conductive adhesives 51a, 51b, and 51c may be the same type of non-conductive adhesive. In this specification, "non-conductive adhesive 51" is used as a collective expression of the first to third non-conductive adhesives 51a, 51b, and 51c if not specifically stated.

In this specification, "adhesive 51" is used as a collective representation of the first to third non-conductive adhesives 51a, 51b, and 51c and the conductive adhesive 51bb, unless otherwise specified.

The first to third non-conductive adhesives 51a, 51b, and 51c and the conductive adhesive 51bb may be adhesives hardened by ultraviolet rays or heat.

The non-conductive adhesive 51 may be selected from known non-conductive adhesives including conductive adhesives comprising particles of non-conductive materials such as silica and glass.

A method of manufacturing the head suspension 31 according to the embodiment of the present invention will be described.

To apply the non-conductive adhesive 51 to the opening (attachment member) 43, an adhesive application system 101 such as shown in FIG. 6 is used.

The adhesive application system 101 includes a syringe 103 having a circular cross-section and containing a non-conductive adhesive 51 . The syringe 103 has a plunger 105 for pushing out the adhesive 51 , a discharge needle 107 at the lower end of the syringe 103 , and a circular cap 109 at the upper end of the syringe 103 . Cover 109 has holes 115 to draw compressed air from compressor 111 through air duct 113 . The air duct 113 includes a solenoid valve 117 . The solenoid valve 117 has an inlet 117A, an outlet 117B that receives compressed air from the compressor 111 , an outlet 117B that supplies compressed air, and a discharge port 117C that discharges the compressed air out of the air duct 113 . The outlet 117B is selectively connected to one of the inlet 117A and the discharge port 117C. The compressor 111 is connected to a drive controller 119 which controls the adhesive applying operation as a whole.

In the adhesive application system 101, as shown in FIG. 7, a drive controller 119 provides operating instructions. In response to this instruction, compressor 111 sends compressed air into injector 103 . Then, the piston 105 descends to extrude the first non-conductive adhesive 51a. The adhesive 51a is pushed out of the discharge needle 107 under pressure. As shown in FIGS. 5A and 5B , the discharged adhesive 51 a is thinly applied to the supports 33 a 1 and 33 a 2 . This corresponds to step S11 of FIG. 7 . Here, "applied thinly" means that the first non-conductive adhesive 51a applied for electrical insulation is thinner than the second non-conductive adhesive 51b applied for fixing in step S13. Thinly applying the first non-conductive adhesive 51 a for electrical insulation will make the size of the opening (attachment member) 43 as small as possible in consideration of the size of the piezoelectric element 13 embedded in the opening 43 .

Then, ultraviolet (UV) rays are irradiated to the part to which the first non-conductive adhesive 51a has been applied to temporarily set the adhesive 51a. This is step S12 of FIG. 7 . This step forms a first non-conductive adhesive layer (thin insulating layer) 51a1 on supports 33a1 and 33a2.

Steps S11 and S12 correspond to the first operation of "applying and hardening the adhesive at the attachment parts one by one" specified in claim 2 .

Then, the drive controller 119 issues the next command to send compressed air from the compressor 111 to the injector 103 . Then, the piston 105 descends to extrude the commanded amount of the second non-conductive adhesive 51b. Under pressure, the adhesive 51b is pushed out of the discharge needle 107 and applied to the first non-conductive adhesive layer 51a1 formed on the supports 33a1 and 33a2. This is step S13 of FIG. 7 .

Then, the piezoelectric element (PZT) 13 is mounted on the second non-conductive adhesive 51b in step S14 of FIG. 7 . In step S15 of FIG. 7, ultraviolet rays are irradiated to the member to which the adhesive is applied to temporarily harden the adhesive 51b. This forms a second nonconductive adhesive layer 51b1 on the first nonconductive adhesive layer 51a1.

If the piezoelectric element (PZT) 13 is placed by strongly pressing it toward the first nonconductive adhesive layer 51a1 in step S14, the second nonconductive adhesive layer 51b1 will be very thin. Even in this case, if the first non-conductive adhesive layer 51a1 is formed to a thickness of 10 μm or more, electrical insulation between the common electrode 19 of the piezoelectric element 13 and the supports 33a1 and 33a2 can be ensured.

Steps S13 to S15 correspond to the second operation of "applying and hardening the adhesive at the attachment parts one by one" specified in claim 2 . That is, the example of FIG. 7 applies the non-conductive adhesive 51 twice to the supports 33 a 1 and 33 a 2 formed at the opening (attachment member) 43 of the base 33 .

Then, step S16 of FIG. 7 heat-treats the head suspension 31 to completely harden the first and second non-conductive adhesive layers 51a1 and 51b1.

As shown in FIGS. 5A and 8, steps S15-1 and S15-2 may be located between steps S15 and S16. Step S15-1 fills the gap 50 between the piezoelectric element 13 and the vertical wall 43a of the opening (attached part) 43 with the third non-conductive adhesive 51c, and Step S15-2 applies the adhesive 51c to the part Ultraviolet rays are irradiated to temporarily harden the adhesive 51c. Steps S11 to S16 in FIG. 8 are the same as steps S11 to S16 , so details are not repeated here.

Steps S15 - 1 and S15 - 2 correspond to the third operation of "applying and hardening the adhesive at the attachment parts one by one" specified in claim 2 . That is, the example of FIG. 8 applies the non-conductive adhesive 51 three times to the supports 33 a 1 and 33 a 2 formed at the opening (attachment member) 43 of the base 33 .

According to the present embodiment, a portion where the base 33 and the connection plate 37 overlap corresponds to the driving side Y of the piezoelectric actuator 11 .

The piezoelectric element 13 is located at a predetermined position close to the inner peripheral surface of the opening 43 . As shown in FIGS. 5A and 5B , the wiring portion 55 (made of copper, for example) of the flexure 39 and the common electrode 19 of the piezoelectric element 13 are exposed toward each other. Between the wiring portion 55 and the common electrode 19, there is a small space of several tens of micrometers. In order to electrically connect the wiring portion 55 and the common electrode 19 to each other in a small space, a conductive adhesive 57 is arranged in the small space as shown in FIGS. 5A and 5B . Instead of the conductive adhesive 57, wire bonding, soldering, ultrasonic welding, or any other connection technique may be used to connect the wiring portion 55 and the common electrode 19 to each other.

In order to electrically connect the first and second electrodes 15 and 17 of the piezoelectric element 13 to the base 33, a pair of conductive adhesives 53a and 53b are arranged. In FIGS. 5A and 5B , reference numeral 59 is a metal base of the flexure 39 , and reference numeral 61 is an electrical insulating layer of the flexure 39 .

The operation of the head suspension 31 according to the present embodiment will be explained. Assume that the first and second electrodes 15 and 17 of the piezoelectric element 13 are grounded and the common electrode 19 thereof receives a predetermined voltage.

As shown in FIG. 2 , the end face 23 of the first electrode 15 contracts and the end face 25 of the second electrode 17 extends, and thus, the piezoelectric element 13 is deformed into a trapezoid. That is, the piezoelectric element 13 moves precisely in the direction Z to move the load beam 35 on the drive side Y in the swing direction (lateral direction of the head suspension 31 ). If the common electrode 19 is grounded and the first and second electrodes 15 and 17 receive a predetermined voltage, the piezoelectric element 13 moves precisely in the direction -Z to move the load beam 35 on the driving side Y in the swing direction.

The head suspension 31 including the piezoelectric actuator 11 requires three electrical systems for the first and second electrodes 15 and 17 of the piezoelectric element 13 and the common electrode 19 . This configuration makes the wiring work to the piezoelectric element 13 simple and reliable.

The base 33 accommodates the piezoelectric element 13 in the opening 43 and supports the piezoelectric element 13 from the bottom. The opening 43 of the base 33 surrounds the piezoelectric element 13 to easily position the piezoelectric element 13 and protect the fragile piezoelectric element 13 from damage.

The common electrode 19 and the wiring portion 55 face each other and are electrically connected to each other by a single connection (conductive adhesive 57 ). This configuration reduces the number of wires to be placed on the flexure 39 and increases the number of flexures to be produced from the material.

The head suspension 31 according to the present embodiment employs a single piezoelectric element 13 to reduce the number of parts, simplify parts management, and reduce the cost of the head suspension 31, compared with a head suspension using a pair of piezoelectric elements.

The head suspension 31 according to the present embodiment arranges the supports 33 a 1 and 33 a 2 in the opening (attachment member) 43 to support the common electrode 19 of the piezoelectric element 13 . The piezoelectric element 13 is fixed to the supports 33a1 and 33a2 using a plurality of adhesive layers (first non-conductive adhesive layer 51a1 and second non-conductive adhesive layer 51b1). Among the plurality of adhesive layers, the adhesive layer (first non-conductive adhesive layer 51a1 ) that is in contact with the supports 33a1 and 33a2 is electrically insulating.

The head suspension 31 according to the present embodiment thus properly maintains electrical insulation between the piezoelectric element 13 and the opening (attachment member) 43 and works completely.

The method of manufacturing the head suspension according to the present embodiment repeats the operation of applying the adhesive 51 to the opening (attachment member) 43 and hardening the adhesive 51 a plurality of times to fix the piezoelectric element 13 to the opening (attachment member). Parts) 43. Of the multiple operations, at least the adhesive 51 applied in the first operation is electrically insulating.

The adhesive (first non-conductive adhesive 51 a ) applied in the first operation ensures electrical insulation between the piezoelectric element 13 and the opening (attachment member) 43 so that the head suspension 31 can fully operate.

After many repetitions of the operation, the adhesive 51 is strongly hardened at the opening (attachment part) 43 so that the adhesive 51 never seeps out or spreads.

Thus, the method of manufacturing the head suspension according to the present embodiment ensures electrical insulation between the piezoelectric element 13 and the opening (attachment member) 43, allows the head suspension 31 to fully operate and ensures rigid balance and Appropriate vibration characteristics.

Each adhesive used in multiple repetitions of the operation may be electrically insulating. This improves the insulation capability compared to the case where the conductive adhesive is used in every adhesive application operation except the first adhesive application operation.

According to the present embodiment, the first adhesive application operation (steps S11 and S12 of FIGS. 7 and 8 ) ensures electrical insulation and the subsequent adhesive application operation (steps S13 to S15 of FIGS. 7 and 8 and Steps S15-1 and 15-2) ensure electrical insulation and fixation of the piezoelectric element 13 .

Compared with the related art of electrically insulating and fixing the piezoelectric element 13 in one adhesive application operation, the present embodiment does not require a wide space or design margin between the piezoelectric element 13 and the opening (attachment member) 43 .

Accordingly, the method of manufacturing the head suspension according to the present embodiment can make the size of the opening (attachment member) 43 as small as possible in consideration of the size of the piezoelectric element 13 embedded in the opening 43 . The head suspension of this embodiment can flexibly meet the requirement of miniaturization.

Of the multiple iterations of the adhesive application operation, the first adhesive application operation may employ an electrically insulating adhesive and the subsequent adhesive application operations may each employ an adhesive that is not electrically insulating. For example, the second and subsequent adhesive application operations (steps S13 to S15 in FIGS. 7 and 8 and S15-1 and 15-2 in FIG. 8 ) may employ a conductive adhesive as the adhesive 51, which The mixture does not contain insulating materials (such as silica particles or glass particles).

Compared with the case of using a non-conductive adhesive containing insulating silica or glass particles for the second and subsequent adhesive application operations, this technique improves the strong fixing of the piezoelectric element 13 to the opening (attachment member) 43 bond strength.

The method of manufacturing the head suspension according to the present embodiment arranges the non-conductive adhesive 51 between the piezoelectric element 13 and the opening (attachment member) 43 to correctly transfer the transfer of the piezoelectric element 13 to the load beam 35 , and at the same time ensure electrical insulation between the common electrode 19 of the piezoelectric element 13 and the base 33 .

A method of manufacturing a head suspension according to another aspect of the present invention will be described. This aspect applies (similar to step S11 of FIG. 7 ) a non-conductive adhesive (first non-conductive adhesive 51a) for electrical insulation to the opening (attachment member) 43, temporarily sets (similar to step S12 of FIG. 7 ) nonconductive adhesive 51a to form an insulating adhesive layer (first nonconductive adhesive layer 51a1), and an adhesive (second nonconductive adhesive 51b) for fixing the piezoelectric element 13 is applied ( Similar to step S13 of FIG. 7 ) to the opening (attachment member) 43 to which the insulating adhesive layer 51a1 has been formed, the piezoelectric element 13 is placed (similar to step S14 of FIG. 7 ) to which the fixing adhesive 51b has been applied. Opening (attachment member) 43, after placing piezoelectric element 13 temporarily provided (similar to step S15 of FIG. 7) fixing adhesive 51b to form a fixing adhesive layer (second non-conductive adhesive layer 51b1) , and completely harden (step S16 similar to FIG. fixed to the opening (attachment part) 43 .

The method of manufacturing the head suspension according to the above aspect ensures proper electrical insulation between the piezoelectric element 13 and the opening (attachment member) 43, allows the head suspension 31 to fully operate, and ensures the balance of rigidity and rigidity of the head suspension 31. Appropriate vibration characteristics.

The above-mentioned non-conductive adhesive for electrical insulation and adhesive for fixing are adhesives that are hardened by ultraviolet rays or heat. Temporary hardening of such an adhesive may be performed by ultraviolet rays and complete hardening of such an adhesive may be performed by heat.

The adhesive used for fixing may be a conductive adhesive or a non-conductive adhesive. If the adhesive used for fixing is a conductive adhesive, compared with the case where a non-conductive adhesive containing insulating silica or glass particles is used for the second and subsequent adhesive application operations, it will improve the The piezoelectric element 13 is strongly fixed to the bonding strength of the opening (attachment member) 43 .

The method of manufacturing the head suspension according to the above aspect can perform filling of the piezoelectric element 13 and the opening using the adhesive 51 (corresponding to step S15-1 of FIG. 8 ) between forming the fixing adhesive layer and fixing the piezoelectric element. The gap 50 between the (attached members) 43 and the adhesive 51 in the gap 50 are temporarily hardened (corresponding to step S15-2 of FIG. 8 ).

The adhesive 51 located between the piezoelectric element 13 and the opening (attachment part) 43 correctly transmits (transfers) the twist of the piezoelectric element 13 to the load beam 35 .

The piezoelectric element fixing operation can completely harden the insulating non-conductive adhesive (first non-conductive adhesive 51a), the fixing adhesive (second non-conductive adhesive 51b), and the adhesive in the gap 50 ( A third non-conductive adhesive 51 c ) to fix the piezoelectric element 13 to the opening (attachment member) 43 .

The adhesive (third non-conductive adhesive 51c) to be applied to the gap 50 may be a non-conductive adhesive.

The non-conductive adhesive 51c located between the piezoelectric element 13 and the opening (attachment part) 43 correctly transmits (transfers) the twist of the piezoelectric element 13 to the load beam 35 and ensures that the common electrode 19 of the piezoelectric element 13 is connected to the Electrical insulation between bases 33 .

The present invention is not limited to the above-mentioned embodiments and the present invention can be modified without departing from the gist and technical idea of the present invention mentioned in the claims and the specification. A head suspension according to such a modification and a method of manufacturing the head suspension also fall within the scope of the present invention.

For example, according to a variant of the invention, the flexures 41 a and 41 b and the opening 43 are formed on the actuator plate 34 instead of the base 33 . In this regard, the term "base" refers to the base 33 alone or the base 33 plus the actuator plate 34 . Accordingly, the "substrate" specified in the claims can be regarded as a base or an actuator board. For example, an opening (attachment member) formed on the base (base) can be regarded as an opening (attachment member) formed on the actuator plate (base).

According to the present embodiment, the piezoelectric actuator 11 employs one piezoelectric element 13 located in the opening 43 of the base 33 . This does not limit the invention. According to another variant of the present invention shown in FIG. 9, the piezoelectric actuator 83 employs a pair of piezoelectric elements 81a and 81b and according to the present invention the pair of piezoelectric elements 81a and 81b are passed through an applied adhesive (or multiple adhesive) is set in the opening (attachment member) 43 of the base 33 .

The adhesive 51 used in the present invention may be made by adding a thixotropic agent to a known non-conductive adhesive (for example, by adding insulating particles such as silica particles and glass particles to a conductive adhesive). Special adhesive with thixotropic properties. Such a thixotropic adhesive 51 is a sol when applied to the gap 50 .

Thixotropic agents prevent known non-conductive adhesives from falling or spreading when applied to an object. The thixotropic agent can be selected from the group consisting of powdered silica, quartz powder, organic bentonite, talc, montmorillonite, clay, polyamide resin, and the like.

A thixotropic agent 51 in sol is applied into a gap 50 between the piezoelectric element 13 and the opening (attachment member) 33 of the head suspension 31 . Since the adhesive 51 is a sol, it is easily applied to the gap 50 .

When applied, the thixotropic adhesive 51 as a sol gradually changes to a gel and loses fluidity, and thus the applied adhesive 51 never seeps or spreads.

Thus, it will be easy to control the application amount of the adhesive 51 , automate the application process of the adhesive 51 and ensure proper rigidity balance and vibration characteristics of the head suspension 31 .

Claims (9)

1. A head suspension having a piezoelectric element, a base and a load beam, wherein the piezoelectric element deforms in response to a voltage applied thereto, the base having a base for attaching the piezoelectric element The opening of the attachment part, the load beam is fixed to the base so that the front end of the load beam moves in a swing direction according to the deformation of the piezoelectric element, the head suspension includes: a support surface formed in the opening configured to support an electrode surface of the piezoelectric element; and A plurality of adhesive layers are formed on the support surface for fixing the piezoelectric element to the support surface, and one adhesive layer in contact with the support surface is electrically insulating. 2. A method of manufacturing a head suspension having a piezoelectric element, a base, and a load beam, wherein the piezoelectric element deforms in response to a voltage applied thereto, the base having a Attaching an opening of an attachment part of a piezoelectric element, the load beam being fixed to the base so that a front end of the load beam moves in a swing direction according to deformation of the piezoelectric element, the method includes: applying and curing adhesives at the attachment parts one after the other to secure the piezoelectric element to the attachment parts, at least one adhesive being electrically insulating, the Adhesive is first applied and hardened at the attachment part. 3. The method of claim 2, wherein: The adhesives applied and hardened one by one at the attachment parts are each electrically insulating. 4. A method of manufacturing a head suspension having a piezoelectric element, a base, and a load beam, wherein the piezoelectric element deforms in response to a voltage applied thereto, the base having a Attaching an opening of an attachment part of a piezoelectric element, the load beam being fixed to the base so that a front end of the load beam moves in a swing direction according to deformation of the piezoelectric element, the method includes: applying a non-conductive adhesive for electrical insulation to the attachment member; temporarily hardening the non-conductive adhesive to form an insulating adhesive layer; applying a fixing adhesive for fixing the piezoelectric element to the insulating adhesive layer; placing the piezoelectric element on the fixing adhesive applied to the attachment member; Temporarily hardening the fixing adhesive to form a fixing adhesive layer after placing the piezoelectric element on the fixing adhesive; and The insulating adhesive layer and the fixing adhesive layer are completely hardened to fix the piezoelectric element to the attachment member. 5. The method of claim 4, wherein: The non-conductive adhesive and fixing adhesive are adhesives hardened by ultraviolet rays and heat; and Temporarily hardening the non-conductive adhesive and temporarily hardening the fixing adhesive are performed by ultraviolet rays. 6. The method of claim 4, wherein: The non-conductive adhesive and fixing adhesive are adhesives hardened by ultraviolet rays and heat; and Complete hardening of the insulating adhesive layer and the fixing adhesive layer is performed by heat. 7. The method of claim 4, wherein: The fixing adhesive is one of a conductive adhesive and a non-conductive adhesive. 8. The method of claim 4, after temporarily hardening the fixing adhesive, further comprising: applying an adhesive to fill a gap between the piezoelectric element and the attachment member; and temporarily hardening the adhesive filled in the gap, The adhesive filled in the gap is completely hardened when the insulating adhesive layer and the fixing adhesive layer are completely hardened, thereby fixing the piezoelectric element to the attachment member. 9. The method of claim 8, wherein: The adhesive applied to the gap is a non-conductive adhesive.

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